The Truth About TSA Airport Scanning

What's all this about the government trying to give us cancer and storing clothing-free images? Here's the truth about what you'll encounter—the radio frequencies, radiation and patdowns—when flying during Thanksgiving

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There are two kinds of scanning devices­, back-scatter and millimeter wave. Back-scatter scanning machines send narrow, low-density X-ray beams over the subject, front and back, at high speeds, which just barely penetrate the clothing. The X-ray radiation reflects off the body—and off of any objects hidden on that person. The process takes between 6 and 8 seconds.

Millimeter-wave (mmw) machines are typically composed of twin vertical arrays of extremely high-frequency transmitters that circle the passenger and create a three-dimensional image. The transmitters emit beams of radio frequency (RF) energy, which bounce off sub–clothing surfaces and expose hidden items. Like back-scatter machines, the mmw scan requires several seconds before an image is produced.

Where are the machines, and who makes them?

These technologies are now in use at 65 U.S. airports—including all of the major ones, such as JFK in New York and Chicago's O'Hare—with more on the way. As of October, 189 back-scatter units and 152 mmw scanners were operational, and the TSA is looking to push the total number of machines to more than 1000, with the goal to scan two out of every three air travelers by 2011.

In October 2009, the TSA awarded Rapiscan a $25.4 million contract to supply airport checkpoints with its Secure 1000 model back-scatter X-ray machine. The administration also purchased and tested 40 of L-3 Communication's ProVision Advanced Imaging Technology. Also-rans in the race to defend our skies included American Science & Engineering's back-scatter SmartCheck, which apparently took too long—40 seconds—and British outfit Smiths Detection, with its eqo mmw screening system.

What can they actually see?

According to the TSA, only what it requires to keep weapons and explosives off airplanes. The back-scatter device and the mmw machine each produce different kinds of images. While the former creates an almost cartoonish two-dimensional snapshot of the inspection subject, the latter produces a holographic, 3D image.

Conscious of privacy concerns, the TSA has given numerous assurances that every machine used in airports will feature face-and-genitalia-obscuring checks installed—the so-called "modesty algorithm." TSA officials also stress that the body scanners are incapable of data storage and that once an inspection ends and the image is cleared, it disappears forever.

At the same time, U.S. marshals at a courthouse in Florida allegedly stored tens of thousands of these images, and the TSA itself has publicly admitted that scanning machines do in fact possess the capability to "store, print, record and export" the images it creates, but contends that this ability is only used for "testing, training and evaluation."

Can they cause cancer?

The likelihood of these machines being the direct cause of cancer is very slim. Of the two technologies, the mmw scanners, which beam nonionizing radiation, are less dangerous. There is no denying back-scatter technology exposes the inspected individual to small doses of radiation, which can cause cancer when the doses add up (pdf). The Rapiscan Secure 1000 serves up about 3 microrems per scan, according to the TSA. Francis Masse, director of the MIT Radiation Protection Office considers 5000 millirems (equal to 5,000,000 microrems) of annual radiation exposure adequately safe.

Maurine Fanguy, of the TSA's Office of Security Technology has said it would require "thousands and thousands" of advanced imaging technology (AIT) inspections to equal "one chest X-ray" (around 3300 by our estimates). Still, various eminent voices in the field of radiation—the chief of Columbia University's Center for Radiological Research, and several scientists at the University of California, San Francisco, for example—believe the government-enforced dosing could be a public-health disaster if the radiation dose on the skin are greater than the TSA believes.

What are my rights?

So you're a modest, law-abiding citizen who's afraid of radiation exposure? There's a way around the virtual strip search: the so-called Opt Out. By all accounts, this results in a thorough patdown, with a close examination of all personal belongings. If that's too intrusive for you, there's always Amtrak.

Why are pilots concerned about their health?

Because of the frequency they are in the air, some pilots are concerned that the extra radiation exposure will put them at greater risk of health issues. In a recent letter to the TSA (which we fact-check here), Captain Dan Bates, president of the Allied Pilots Association (APA), wrote: "We already experience significantly higher radiation exposure than most other occupations, and there is mounting evidence of higher-than-average cancer rates as a consequence."

Past studies have suggested that veteran pilots are disproportionately susceptible to cancer—and malignant melanoma, in particular—due to prolonged exposure to cosmic ionizing rays. A survey of Icelandic commercial flyboys, conducted in 2000 by the University of Iceland's Dr. Vilhjálmur Rafnsson, found that skin cancer rates for pilots were between 10 and 25 times higher than that of the general public. That same year, the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) issued a report on ionizing radiation, which noted that a career in the air exposes pilots and crew to more occupational radiation—3 millisieverts annually—than X-ray professionals, uranium miners and nuclear power plant employees.